This invention relates to magnetic image recording devices in which a magnetic latent image is formed on a magnetic medium, and in particular to a magnetic image recording device in which desired portions (recording portions or non-recording portions) of a magnetic medium having a uniform magnetization pattern are selectively heated so that the heated portions are different in the intensity of magnetization from the remaining portions, whereby the magnetic latent image of an image to be recorded is formed on the magnetic medium.
In conventional magnetic image recording devices, in order to write data on the magnetic medium, the polarity of magnetization in a desired portion of a uniformly magnetized magnetic medium is inverted with a magnetic head. This is described, for example, in related copending applications 235,366 filed Feb. 19, 1981 and 309,135, filed on Oct. 6, 1981 and corresponding of Japanese application 55-139411.
Accordingly, in order to write data at a density of about ten pieces/mm for every line, it is necessary to employ about 1,000 to 2,000 magnetic heads. However, manufacturing a magnetic head assembly having such a high density is considerably difficult.
There is a known device in which a laser beam is used to heat a magnetic medium to temperatures higher than its Curie temperature (or a magnetic compensation temperature depending on the material) to invert the polarity of magnetization of magnetic medium and thereby write data. In general, Curie temperatures are relatively high and this device is therefore disadvantageous in that a large quantity of energy is required for heating the magnetic medium, resulting in high operating costs.
Such a data writing method may be applied to a magnetic image recording operation, wherein toner particles are made to stick to the medium in accordance with the magnetization polarity of different portions of the medium. However, since it is difficult to cause magnetic toner to stick onto demagnetized portions of the magnetic medium, the resultant image is not reproduced with high fidelity; i.e., the density of the image is not uniform.